[R] nested random effects

Federico Calboli f.calboli at imperial.ac.uk
Wed Mar 23 18:33:47 CET 2005

On Wed, 2005-03-23 at 11:58 -0500, Shaw, Philip (NIH/NIMH) wrote:
> Hi
> I am struggling with nested random effects and hope someone can help.
> I have individuals (ID) who are nested within families (FAM).  I want to
> model an outcome variable, and take account of the intercorrelation of
> individuals within each family. 
> I think this amounts to two random effects, one nested within the other.
> How can I model this in R?
> So far I have tried using the library(nlme), and then
> Y~ID, random=~1|ID*FAM, 

An interaction random effect/fixed effect is noted as 

random ~1|random/fixed

in your case random =~1|ID/FAM (but I don't uderstand why indiviuals
withing families are fixed and and families are random, but there you

Check out Pinheiro and Bates Ch1, especially pg 23 onwards.


Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St Mary's Campus
Norfolk Place, London W2 1PG

Tel  +44 (0)20 7594 1602     Fax (+44) 020 7594 3193

f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com

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